In the mangroves off the east coast of Central America, at the edge of the Mesoamerican Reef, the world is divided in two: the above and the below. As we killed the engines and poled the skiff from the hot April sun into the shade of the forest, Will Heyman, my marine biologist companion, and I gazed into the simplicity above. We saw the green crowns of one of the least diverse of all tropical forests, where there is often but a single species of tree, the red mangrove.
Salinity, storm waves, and oxygen-poor mud discourage understory growth in the mangroves, so there was little beneath the canopy for us to see. The occasional orchid. Rarely, a vine. A troop of fiddler crabs guarding holes in the mud. A big mangrove crab low on a trunk. Some insects. A tricolored heron perched on the stilt of a mangrove root.
I leaned over the gunwale to sample the mud around the roots, scooping up sherds of pottery. The mangroves of the Mesoamerican Reef were once at the fringe of the ancient Maya civilization. I contemplated slipping a souvenir into my pocket—with such a lode here, what possible harm? “Strictly catch-and-release,” Heyman said. With a splashing of jettisoned sherds, we poled to another spot. There, in the still water, we witnessed the miracle of the below.